The invention discloses a quantitative analysis method for polychlorobiphenyls in dry food packaging paper. The quantitative analysis method is used for measuring the contents of seven main polychlorobiphenyls substances in the dry food packaging paper based on a gas chromatography-tandem mass spectrometer, and includes the steps of preparing an internal-standard solution, a standard work solution and a sample solution, carrying out GC-MS/MS analysis and calculating the measuring result. The optimized detection method is easy and convenient to operate, sensitive in response and accurate in quantitative analysis, the interference caused by complex sample substrates is effectively reduced, an analytical instrument aims at allowing target objects to have good signal responses and the good linear dependence, the detection limits of the seven polychlorobiphenyls substances are 0.99 ng/g, 0.74 ng/g, 1.05 ng/g, 1.29 ng/g, 0.75 ng/g, 1.11 ng/g and 1.19 ng/g respectively, the repeatability is smaller than 10%, and the adding standard recovery rate ranges from 68.4% to 147.0%. The quantitative analysis method is high in sensitivity, good in repeatability and recovery rate and suitable for measuring quantitative analysis of trace target objects in the dry food packaging paper.